As more and more emphasis is put on energy conservation, homes and workplaces are being more tightly sealed than in the past in order to minimize heat losses. As sealing is improved, there is also less opportunity for the dilution and escape of any toxic gases, which could result from malfunctioning or misadjusted heating units or the like. Of particular interest in the home or normal workplace environment is the buildup of carbon monoxide.
There are a number of known ways to measure carbon monoxide, including volumetric chemical absorption, catalytic heat of reaction, spectroscopy, thermal conductivity, and surface absorption semiconductors. Volumetric chemical absorption is typified by the well-know Orsat analyzers, however, these are not capable of being automated for continuous sampling. Devices which operate on the principles of catalytic heat of reaction, spectroscopy and thermal conductivity can provide continuous analysis, however, they tend to lack sensitivity, are relatively expensive, and have relatively high power consumption to be practical for continuous household use. Surface absorption devices meet most of the requirements for household and workplace use, however, they also respond to many commonly used non-toxic substances such as hair sprays and other aerosol products, and are thus considered to be impracticable.
Because of the foregoing, it has now become desirable to develop a carbon monoxide monitor which is practical for continuous use in the home or workplace.